Despite the increasing importance of cash flow management in the financial Supply chain, limited works have been conducted in this field. This research optimizes the flow of money in the medical Supply chain from the viewpoint of a distribution company. In this context, the focal company receives the medical supplies from the upstream suppliers and sells them to the downstream retailers and makes payments to suppliers with earned money from retailers. The imbalance between the cash inflow and outflow causes the imposition of a penalty for late-payments and Supply risk as a result of the poor reputation in the market. In this context, the question is which payment sequence will minimize the total monetary outflows and the risk of Supply. To answer this question, a bi-objective 0-1 linear programming model was developed. Solving the model by genetic algorithm determined the best sequence of payments and minimized the cash outflow as well as the risk of violation of the due date for the invoices.